#include<stdio.h>
#include<string.h>

char* StrChoice(char *arr, char *ret)
{
	int i = 0, j = 0;
	int len = strlen(arr);
	for (; i < len; i+=2, j++)
	{
		ret[j] = arr[i];
	}
	return ret;
}

int main()
{
	char arr[100] = {0};
	char ret[100] = {0};
	scanf("%s", arr);
	printf("%s\n", StrChoice(arr, ret));

	return 0;
}
